Survivable Remote Site Telephony (SRST) is a Cisco Unified Communications Manager (CUCM) call processing backup mechanism that allows Cisco IP phones to register to a Cisco router.
What is SRST used for?
Cisco Unified SIP SRST enables the SIP IP Phones to continue making and receiving calls to and from the PSTN. They also can continue making and receiving calls to and from other SIP IP Phones by using the dial peers configured on the router.
What is SRST mode on Cisco phone?
SRST is an IOS feature that enables routers to provide call-handling support for Cisco IP Phones if they lose their connection to a remote Primary CUCM which can occur if the WAN connection to the main site is down.
Why does a phone go into preservation mode?
This happens when the remote phones lose connectivity with the CUCM server at your primary office. I suggest you look into the stability of your remote site connectivity – be it MPLS, VPN ect. I suspect you are experiencing packet loss or high latency/jitter between your office and remote site.
What is SRST fallback?
MGCP fallback enables a gateway to act as local call control when the CUCM server to which the remote site phones and gateway register is offline or WAN connectivity is lost (in which case, Cisco Unified SRST kicks in and offers call control functionality).
What does CM fallback service mean?
SRST only provides basic survivability for remote sites in the event of a WAN outage. When the IP phone is in fall back mode the prompt on the phone displays the message. “CM Fallback Service Operating” to inform users fallback mode is active.
How do I activate my CME SRST license?
It will cover how to activate the CME/SRST feature license.
Go to global configuration mode. Issue the config t command.Issue the telephony-service command.Issue the max-dn
What port does SCCP use?
TCP Port 2000 is the port reserved for Cisco SCCP (Skinny) Protocol.
What is Cisco CME?
Cisco Call Manager Express (CME) is an enhanced IP telephony solution that is integrated into Cisco IOS. It is an ideal solution for small business customers to efficiently use their existing IP data connectivity to incorporate the deployment of voice and IP telephony.
How do I reset my phone SRST?
Navigate to System > Device Pool then find and select the pool with which the SRST device should be associated. Click on the “SRST Reference” drop-down and select the device that was created in the previous step. Save everything, and do a Reset. This will reset the phones in the device pool.
What is self preservation mode?
Self-preservation is essentially the process of an organism preventing itself from being harmed or killed and is considered a basic instinct in most organisms. Most call it a “survival instinct”.
